With the rapid development of Internet technology and the increasing user demand for applications of the Internet, various data centers have been created. Development of virtualization technology makes it possible to achieve a large number of virtual machines (VM) in the data centers. These virtual machines can essentially operate as a physical machine and perform a variety of functions such as Web servers or database servers. Currently, in the data centers, not all servers run on a virtual machine because of performance problems or safety considerations. Users are more willing to place some important applications on a physical machine. However, applications using a database may run on a virtual machine, and the users may access the virtual network via their physical devices. While virtualization brings unprecedented flexibility to service providers, a two-layer structure tends to be fixed and may not easily be applied to the dynamic characteristics of virtual machines. Under the conventional techniques, to achieve communication between a VM of a data center and a VM or a storage device of another data center, users may create a virtual network using extended LAN (Vxlan) technology to connect the VMs.
Vxlan technology creates a two-layer network on a three-layer IP network, and a data header generated by a VM may be transmitted to a remote data center after packaged into an IP header. In the remote data center, the IP header may be removed, and original data packets may be delivered to a target destine. An IP packaging mechanism allows a two-layer broadcasting area to be extended to any number of remote centers and allows different data centers or different parts in the same data center to be in the same two-layer broadcasting area. A Vxlan function normally resides in the host management program and works with the virtual switch management program in conjunction. However, existing implementations of Vxlan may not easily be adapted to a mixture of VMs and physical devices in the same logical layer.